In Silico Evaluation, Phylogenetic Analysis, and Structural Modeling of the Class II Hydrophobin Family from Different Fungal Phytopathogens

The class II hydrophobin group (HFBII) is an extracellular group of proteins that contain the HFBII domain and eight conserved cysteine residues. These proteins are exclusively secreted by fungi and have multiple functions with a probable role as effectors. In the present study, a total of 45 amino acid sequences of hydrophobin class II proteins from different phytopathogenic fungi were retrieved from the NCBI database. We used the integration of well-designed bioinformatic tools to characterize and predict their physicochemical parameters, novel motifs, 3D structures, multiple sequence alignment (MSA), evolution, and functions as effector proteins through molecular docking. The results revealed new features for these protein members. The ProtParam tool detected the hydrophobicity properties of all proteins except for one hydrophilic protein (KAI3335996.1). Out of 45 proteins, six of them were detected as GPI-anchored proteins by the PredGPI server. Different 3D structure templates with high pTM scores were designed by Multifold v1, AlphaFold2, and trRosetta. Most of the studied proteins were anticipated as apoplastic effectors and matched with the ghyd5 gene of Fusarium graminearum as virulence factors. A protein–protein interaction (PPI) analysis unraveled the molecular function of this group as GTP-binding proteins, while a molecular docking analysis detected a chitin-binding effector role. From the MSA analysis, it was observed that the HFBII sequences shared conserved 2 Pro (P) and 2 Gly (G) amino acids besides the known eight conserved cysteine residues. The evolutionary analysis and phylogenetic tree provided evidence of episodic diversifying selection at the branch level using the aBSREL tool. A detailed in silico analysis of this family and the present findings will provide a better understanding of the HFBII characters and evolutionary relationships, which could be very useful in future studies

Arbuscular mycorrhizal fungi as an effective approach to enhance the growth and metabolism of soybean plants under thallium (TI) toxicity

Abstract: Thallium (TI) is a toxic metal that can trigger harmful impacts on growth and metabolism of plants. Utilizing arbuscular mycorrhizal fungi (AMF) proves to be an effective strategy for alleviating heavy metal toxicity in plants. To this end, AMF were applied to mitigate TI toxic effects on the growth, primary and secondary metabolism of soybean plants. Here, TI stress inhibited the growth and photosynthetic parameters of soybean plants. It also increased the oxidative damage as demonstrated by increased levels of oxidative markers, (MDA and lipoxygenase (LOX) activity). However, AMF could mitigate the reduction in growth and photosynthesis induced by TI, as well as the induction of oxidative damage. To overcome TI toxicity, AMF increased the levels and metabolism of osmolytes such as proline in soybean plants. This was in line with the increased activities of key enzymes that involved in proline biosynthesis (e.g., P5CS (pyrroline-5-carboxylate synthetase), P5CR (pyr-roline-5-carboxylate reductase) and OAT (ornithine aminotransferase) under the AMF and/or TI treatments. Furthermore, soybean plants could benefit from the synergism between AMF and TI to enhance the contents of individual (e.g., spermine and spermidine) and total polyamines as well as their metabolic enzymes (e.g., arginine decarboxylase and ornithine decarboxylase). Overall, the combined application of AMF emerges as a viable approach for alleviating TI toxicity in soybean plants

The Antifungal Activity of Ag/CHI NPs against <i>Rhizoctonia solani</i> Linked with Tomato Plant Health

Pathogenic infestations are significant threats to vegetable yield, and have become an urgent problem to be solved. Rhizoctonia solani is one of the worst fungi affecting tomato crops, reducing yield in some regions. It is a known fact that plants have their own defense against such infestations; however, it is unclear whether any exogenous material can help plants against infestation. Therefore, we performed greenhouse experiments to evaluate the impacts of R. solani on 15- and 30-day old tomato plants after fungal infestation, and estimated the antifungal activity of nanoparticles (NPs) against the pathogen. We observed severe pathogenic impacts on the above-ground tissues of tomato plants which would affect plant physiology and crop production. Pathogenic infection reduced total chlorophyll and anthocyanin contents, which subsequently disturbed plant physiology. Further, total phenolic contents (TPC), total flavonoid contents (TFC), and malondialdehyde (MDA) contents were significantly increased in pathogen treatments. Constitutively, enhanced activities were estimated for catalase (CAT), superoxide dismutase (SOD), and ascorbate peroxidase (APX) in response to reactive oxygen species (ROS)in pathogen-treated plants. Moreover, pathogenesis-related genes, namely, chitinase, plant glutathione S-transferase (GST), phenylalanine ammonia-lyase (PAL1), pathogenesis-related protein (PR12), and pathogenesis-related protein (PR1) were evaluated, with significant differences between treated and control plants. In vitro and greenhouse antifungal activity of silver nanoparticles (Ag NPs), chitosan nanoparticles, and Ag NPs/CHI NPs composites and plant health was studied using transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectrophotometry. We found astonishing results, namely, that Ag and CHI have antifungal activities against R. solani. Overall, plant health was much improved following treatment with Ag NPs/CHI NPs composites. In order to manage R. solani pathogenicity and improve tomato health, Ag/CHI NPs composites could be used infield as well as on commercial levels based on recommendations. However, there is an urgent need to first evaluate whether these NP composites have any secondary impacts on human health or the environment

The Antifungal Activity of Ag/CHI NPs against Rhizoctonia solani Linked with Tomato Plant Health

Pathogenic infestations are significant threats to vegetable yield, and have become an urgent problem to be solved. Rhizoctonia solani is one of the worst fungi affecting tomato crops, reducing yield in some regions. It is a known fact that plants have their own defense against such infestations; however, it is unclear whether any exogenous material can help plants against infestation. Therefore, we performed greenhouse experiments to evaluate the impacts of R. solani on 15- and 30-day old tomato plants after fungal infestation, and estimated the antifungal activity of nanoparticles (NPs) against the pathogen. We observed severe pathogenic impacts on the above-ground tissues of tomato plants which would affect plant physiology and crop production. Pathogenic infection reduced total chlorophyll and anthocyanin contents, which subsequently disturbed plant physiology. Further, total phenolic contents (TPC), total flavonoid contents (TFC), and malondialdehyde (MDA) contents were significantly increased in pathogen treatments. Constitutively, enhanced activities were estimated for catalase (CAT), superoxide dismutase (SOD), and ascorbate peroxidase (APX) in response to reactive oxygen species (ROS)in pathogen-treated plants. Moreover, pathogenesis-related genes, namely, chitinase, plant glutathione S-transferase (GST), phenylalanine ammonia-lyase (PAL1), pathogenesis-related protein (PR12), and pathogenesis-related protein (PR1) were evaluated, with significant differences between treated and control plants. In vitro and greenhouse antifungal activity of silver nanoparticles (Ag NPs), chitosan nanoparticles, and Ag NPs/CHI NPs composites and plant health was studied using transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectrophotometry. We found astonishing results, namely, that Ag and CHI have antifungal activities against R. solani. Overall, plant health was much improved following treatment with Ag NPs/CHI NPs composites. In order to manage R. solani pathogenicity and improve tomato health, Ag/CHI NPs composites could be used infield as well as on commercial levels based on recommendations. However, there is an urgent need to first evaluate whether these NP composites have any secondary impacts on human health or the environment